Gas turbine engines may typically include a fan, a compressor, a combustor, and a turbine, with an annular flow path extending axially through each. Initially, the fan, which is powered by the turbine, draws ambient air into the engine. Part of the air flows through the compressor where it is compressed or pressurized. The combustor then mixes and ignites the compressed air with fuel, generating hot combustion gases. These hot combustion gases are then directed from the combustor to the turbine where power is extracted from the hot gases by causing blades of the turbine to rotate. The other part of the airflow from the fan is used to generate forward thrust.
Various components of the gas turbine engine, such as fan, compressor, and turbine airfoils, are subject to centrifugal force, aerodynamic force, tensile and vibratory stress fields due to the high rotational speeds of the gas turbine engine rotors. In addition, since airfoils are cantilevered from the rotor, the airfoils may bend or flex in various directions, experiencing side-to-side, tip, and torsional flutter. Thus, flutter and excitation of the airfoils at resonant frequencies may cause airfoil damage, such as cracking, or failure, such as from low cycle fatigue (LCF) and high cycle fatigue (HCF).
Currently, airfoil design has included hollow airfoils or airfoils having a plurality of pockets in order to reduce the airfoil mass and weight, thereby increasing rotor speed and fuel performance. The hollow airfoils or airfoil pockets may be filled with an elastomeric material for damping. However, the elastomeric material does not resist side-to-side, tip, and torsional flutter or movement of the airfoil. Accordingly, there exists a need for an improved damping device.